1. Field of the Invention
The invention relates generally to electric submersible pump assemblies used for hydrocarbon production recovery. In particular aspects, the invention relates to lubrication of downhole motors used in electric submersible pump assemblies.
2. Description of the Related Art
A typical electrical submersible pump (ESP) system includes a pump that is driven by a motor. Because the ESP system may be disposed at great depths and is inaccessible at this time, the motors are designed to operate for a long period of time without maintenance. Motor oil is used to help lubricate the motor and to dissipate the heat the motor generates during operation. However, leakage often occurs across mechanical seals in an associated seal section during operation. As the motor operates, it heats up, resulting in expansion of components, which in turn leads to leakage. As pressure drops within the motor due to leakage, the motor can become undesirably prone to fluid ingress by external fluids. Intrusion by these fluids can result in shorting out of the motor, contamination, corrosion and other undesirable effects.